Conventionally, many insects have been attracted to lighting fixtures, and many contrivances have been provided as measures against this. In the case of an incandescent light, since the surface temperature of an envelope thereof is high and this light contains very little ultraviolet light, it attracts fewer insects when compared with a fluorescent light.
On the other hand, with lighting fixture, to enhance a decorative effect or to protect a luminescent part from moisture or dusts, a type in which a luminescent part, or light bulb is not exposed but covered with, for example, a rounded enclosure, envelope or a glove usually made of glass is broadly used. In this type of lighting fixture also, there are small holes or gaps between a glove part and a lighting fixture body, or at the top of the lighting fixture, in order to release heat of a luminescent part and so on. Small insects attracted to light come into a glove through these narrow spaces and die within several hours due to lack of water, or heat, and this causes contamination of the interior of the glove.
Conventionally, a structural attempt to diminish these narrow spaces to control insect invasion has repeatedly been made. However, since there is also a problem regarding release of heat generated inside, a decisive measure has not been proposed yet.
In respect of a method for controlling insect invasion into the enclosure of the above described lighting fixtures, it is desired that the problem be solved with consideration given to release of heat.
Moreover, since a lighting fixture may be installed at a high elevation because of its property, enormous efforts are needed for the maintenance of dead insects accumulated inside an enclosure thereof, and so a means of solving such a problem is required.
Furthermore, generally regarding insect-repellent techniques, volatile insect repellent agents have been studied and developed for the conservation of clothes or the like, and now these agents are commercially available.
However, since lighting fixtures are used in a living environment including a living room, taking into consideration that it may be absorbed through the expiratory air of humans, an agent with a high vapor pressure cannot be used. That is, differing from volatile insect repellent agents, lighting fixtures are in an environment where repellent techniques using stimulation on insect olfactory sense cannot be applied. Therefore, a safer repellent technique is strongly required.